//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#include "pxr/base/tf/refPtr.h"

int
Tf_RefPtr_UniqueChangedCounter::_AddRef(TfRefBase const *refBase,
                                        TfRefBase::UniqueChangedListener const &listener)
{
    listener.lock();
    int oldValue = refBase->GetRefCount()._FetchAndAdd(1);
    if (oldValue == 1)
        listener.func(refBase, false);
    listener.unlock();
    return oldValue;
}

bool
Tf_RefPtr_UniqueChangedCounter::_RemoveRef(TfRefBase const *refBase,
                                           TfRefBase::UniqueChangedListener const &listener)
{
    listener.lock();
    int oldValue = refBase->GetRefCount()._FetchAndAdd(-1);
    if (oldValue == 2)
        listener.func(refBase, true);

    listener.unlock();
    return oldValue == 1;
}
